Artificial hand



R. TRAUTMAN.

1,362, 156, Patented Dec. 14, 1920.

PATENT OFFICE.

RAY TRAUTMAN, OF MINNEAPOLIS, MINNESOTA.

ARTIFICIAL HAND.

Application led November 19, 1919.

and more particularly to artificial hands which have rigid lingers and a movable thumb. An object is to provide a thumb member which can be turned upon a pivot at its base so as to be opened or moved away from the fingers and which will be automatically locked securely in its closed position and which, in case it is partly opened for grasping objects, will be prevented from further opening so that the objects may beV held between the thumb and the fingers.

The full objects and advantages or .my invention will appear in connection with the detailed description thereof and the novel4 features embodied in my inventive idea will be particularly pointed out in the claims.

In the accompanying drawings which illustrate the application of my invention in one form,-

Figure 1 is a view partly in side elevation and partly in section with the thumb in its open position. Fig. 2 is a view similar to Fig. 1, with the thumb member in its closed position. Fig. 3 is a view in section on the line 3-8, of Fig. 2, looking in the direction of the arrows, and turned through 90 degrees from the position of Fig. 2. Fig. 4 is an elevational detail view at right angles to the position shown in Fig. 2.

Referring to the drawings, the character 10 designates a hand member to the inner end of which is secured a screw threaded shank 12 for attachment to an arm member in the usual manner. The hand member is provided with rigid fingers 14 which are curved so as to be inthe position naturally assumed by the human fingers in picking up objects. The hand member at the place corresponding to that occupied by the base of the human thumb, is hollowed to form a cavity 16 and a thumb member 18, is pivoted upon a pin 2O which extends through the walls of the cavity 16. near the open end thereof. The rear portion 21 of the thumb member is reduced and a metal piece 22 secured to this reduced portion, extends back Specification of Letters Fatent.

Patented Dec. 14, 1920.

Serial No. 339,027.

into the cavity 16. The metal piece 22, is provided with a slot 24 in which is adapted to slide a pin 26 carried by an arm 28 pivotally mounted upon a pin 30 which is surrounded by a coiled spring 32 which engages and normally holds the arm 28 in the position shown in Fig. 2. Attached to the free end of the arm 28 is a cord 36 which passes through an opening 34 at the rear of the hand member and then over the shoulder of the person in the usual way. The thumb member 18 is under-eut at 38 in order to provide clearance when the thumb member swings into open position.

The operation and advantages of my invention `will be readily understood in connection with the foregoing description. fr hen the cord 36 is pulled from the shoulder of the wearer, the arm 28 is drawn upwardly from the position shown in Fig. 2 toward that shown in Fig. 1, and since the pin 26 travels in an arc of a circle whose center is the pin 30, the thumb member will be caused to move around the pivot-pin 20.

lVhen the cord is released, the spring 82 will tend to move the thumb member into its closed position so that it can be used for grasping objects. On account of the position of the pin 26 in the slot 24, it is obvious that the thumb member when not pulled by the cord 86, willeither be held locked in closed position upon the fingers 14 or in case articles are interposed between the thumb member and the fingers, the thumb will be held locked in a gripping position until pulled by the cord.

I claim:

1. An artificial hand comprising a main member. a thumb member pivoted to said main member, a slotted member attached to the rear of said thumb member, a member engaging in the slot of said slotted member and tending to hold said thumb member iu closed and locked position, and means whereby the wearer may pull said thumb member into open position iu opposition to said holding means.

2, An artificial hand comprising rigid finger members, a thumb member pivoted to the hand, a slotted member attached to the rear of said thumb member, an arm pivoted within the hand, a pin on said arm engaging in said slot, a spring located within the liant., said spring engaging said arm and operating through the engagement of said sol pin in said slot to normally hold said thumb member in closed and looked position, and means whereby the wearer may pull said thumb member into open position in opposition to the holding action of said spring.

3. An artificial hand, comprising rigid l.

finger members, a thumb member pivoted to the hand, a Slotted member attached to the rear of said thumb member, a member engaging in the slot of said slotted member 10 and tending to hold said thumb member in Closed position, and a oord for pulling said thumb member into open position in opposition to said holding means.

RAY TRAUTMAN. 

